1. Field of the Invention
The present invention relates to a system for controlling driving power for an automotive vehicle.
2. Description of the Related Art
There are several types of systems for controlling driving power for an automotive vehicle. A system in which the characteristics of the internal combustion engine change at a predetermined condition is disclosed in Japanese Patent Laid-open Publication (kokai) No. 197,431/1990. In addition, there are systems which have shifting speed stages and which combined the shifting of the speed stage with the charging at an increased pressure. These types of systems can provide high acceleration and responsiveness to acceleration when the vehicle is accelerated without charging by downshifting to a lower speed stage, for instance, to the third speed stage. On the other hand, when the charging is combined with the higher speed stage, substantially the same amount of acceleration can be produced as at the lower speed stage. Further, when acceleration is provided at the higher speed stage while the charging pressure is supplied, higher fuel efficiency is obtained than when acceleration occurs at the lower speed stage without charging pressure.
Conventional systems operate at predetermined conditions, e.g., by shifting the speed stages, for instance, on the basis of vehicle speed and angle of acceleration or by shifting between charging and non-charging on the basis of the angle of the acceleration at each speed stage. These systems, however, make the best use of those characteristics during operation, regardless of various levels of requirements for acceleration.